1. It's a little pompous to refer to one's penis as a phallus, but it is lexically correct.

2. A penis is for urination; when it becomes erect it is a phallus, serving sexual or reproductive purposes.

3. Two representations of phallus:

a. For example, a primitive sculpture that shows a grotesquely large penis is using the organ as a phallus to indicate fertility, or to represent masculine potency in general.

b. Similarly, the exaggerated genitalia in the work of gay artists such as Tom of Finland emphasize the erotic quality of the phallus, sometimes called hyper-masculinity.

4. A penis, phallus or idea of potency symbolized in an object. The most commonly used term, derived from Freudian psychoanalysis, is called a phallic symbol. One example of this is the very last shot of Hitchcock's 1959 thriller NORTH BY NORTHWEST, which wittily shows a passenger train plunging into a tunnel. Because of the prior plot, the audience knows very well that a train has erotic potential, so the last shot indicates sexual intercourse.